My 404 Page isn’t working. I need it to work for Google Verification.

The 404 Error page on my site https://blastcapnews.com is not functioning, or something is overriding it. The 404 page exists but for some reason bad URLs are getting redirected to the home page. I need to stop this from happening so Google Webmaster Tools will verify my site.

How do I make this happen? Do I need to change the 404 page? Or is there something else blocking or overriding the 404?

I do not know HTML. Please someone who understands WordPress and this issue with Google show me click-by-click what to do?

Thanks.